Inverting the Electronic Structure of Diylidylgermylenes by Backbone Modification.

Owing to the strong electron-donating ability of ylide substituents, diylidyltetrylenes are usually highly nucleophilic species with strong donor capacities. Here, we demonstrate that their electronic properties are in fact highly flexible and can be effectively tuned through variation of the substituent in the ylide backbone. Initial density functional theory studies showed that cyano groups are particularly capable in lowering the LUMO energy of diylidyl germylenes thus turning these usually highly nucleophilic species into electrophilic compounds.

Thiophosphinoyl-Tethered Ylide-Substituted Heavier Carbenes: Synthesis, Structures and Stabilities.

The synthesis and structure analysis of a series of mono and diylide-substituted tetrylenes of type YEX and Y E (E=Ge, Sn, Pb; X=Cl or Br) using a thiophosphinoyl-tethered metallated ylide (Y=Ph P(S)-C-P(pip)Ph with pip=piperidyl) is reported, amongst the first ylide-substituted plumbylenes. The tetrylenes feature distinct trends in the spectroscopic and structural properties of the ylide ligand with increasing atomic number of the tetrel element. For instance, an increasingly high-field shifted signal for the thiophosphinoyl group is observed in the P{ H} NMR spectrum as a consequence of the increasing polarity of the element-carbon bond, which likewise results in a shortening of the ylidic C-P bond in the solid-state structure.

Single-Site and Cooperative Bond Activation Reactions with Ylide-Functionalized Tetrylenes: A Computational Study.

Due to their transition metal-like behavior divalent group 14 compounds bear huge potential for their application in bond activation reactions and catalysis. Here we report on detailed computational studies on the use of ylide-substituted tetrylenes in the activation of dihydrogen and phenol. A series of acyclic and cyclic ylidyltetrylenes featuring various α-substituents with different - and -donating capabilities have been investigated which demonstrate that particularly -accepting boryl groups lead to beneficial properties and low barriers for single-site activation reactions, above all in the case of silylenes.

Ylide-Stabilized Phosphenium Cations: Impact of the Substitution Pattern on the Coordination Chemistry.

Although N-heterocyclic phosphenium (NHP) cations have received considerable research interest due to their application in organocatalysis, including asymmetric synthesis, phosphenium cations with other substitution patterns have hardly been explored. Herein, the preparation of a series of ylide-substituted cations of type [YPR] (with Y=Ph PC(Ph), R=Ph, Cy or Y) and their structural and coordination properties are reported. Although the diylide-substituted cation forms spontaneous from the chlorophosphine precursor, the monoylidylphosphenium ions required the addition of a halide-abstraction reagent.

Towards the rational design of ylide-substituted phosphines for gold(i)-catalysis: from inactive to ppm-level catalysis.

The implementation of gold catalysis into large-scale processes suffers from the fact that most reactions still require high catalyst loadings to achieve efficient catalysis thus making upscaling impractical. Here, we report systematic studies on the impact of the substituent in the backbone of ylide-substituted phosphines (YPhos) on the catalytic activity in the hydroamination of alkynes, which allowed us to increase the catalyst performance by orders of magnitude. While electronic changes of the ligand properties by introduction of aryl groups with electron-withdrawing or electron-donating groups had surprisingly little impact on the activity of the gold complexes, the use of bulky aryl groups with -substituents led to a remarkable boost in the catalyst activity.

Cationic Phosphorus Compounds Based on a Bis(1-piperidinyl)-Substituted Carbodiphosphorane: Syntheses, Structures, and C -H Activation.

The use of the bis(1-piperidinyl)-substituted carbodiphosphorane (Ph(Pip)P)C () as an NCN ligand for the stabilization of phosphorus cations was studied. A simple ligand for halide exchange allowed the synthesis and isolation of a series of phosphorus monocations of the type [-PR] (with R = Cl, Br, I, CyCl, Ph). These cations exhibit characteristic NMR and structural properties which nicely correlate with the charge at the central phosphorus atom and the interaction between the ligand and the PR moiety.

Synthesis of Low-Valent Dinuclear Group 14 Compounds with Element-Element Bonds by Transylidation.

Dinuclear low-valent compounds of the heavy main group elements are rare species owing to their intrinsic reactivity. However, they represent desirable target molecules due to their unusual bonding situations as well as applications in bond activations and materials synthesis. The isolation of such compounds usually requires the use of substituents that provide sufficient stability and synthetic access.

Efficient Pd-Catalyzed Direct Coupling of Aryl Chlorides with Alkyllithium Reagents.

Organolithium compounds are amongst the most important organometallic reagents and frequently used in difficult metallation reactions. However, their direct use in the formation of C-C bonds is less established. Although remarkable advances in the coupling of aryllithium compounds have been achieved, Csp -Csp coupling reactions are very limited.

A diamino-substituted carbodiphosphorane as strong C-donor and weak N-donor: isolation of monomeric trigonal-planar L·ZnCl.

The isolation, structural characterization and coordination chemistry of a di(amino)-substituted carbodiphosphorane (CDP) are reported. Compared to the analogue, dianionic bis(iminophosphoryl)methandiides, the CDP is a stronger C-, but much weaker N-donor which led to the isolation of solely C-coordinated metal complexes amongst an unusual monomeric trigonal-planar L·ZnCl complex.

Prevalence and significance of cranial nerve imaging abnormalities in patients with hereditary neuropathies: Clinical implications at the skull base.

Objective: To estimate the prevalence and significance of cranial nerve (CN) imaging abnormalities in patients with hereditary neuropathy and discuss clinical implications.

Methods: We retrospectively analyzed data from patients at four tertiary academic medical centers with hereditary neuropathy diagnoses who had undergone gadolinium-enhanced magnetic resonance imaging (MRI) of the brain or skull base between 2004 and 2018. MRI scans, as well as computed tomography imaging when available, were reviewed and bivariable analysis was performed to identify predictors of CN abnormalities on imaging.

Towards the Preparation of Stable Cyclic Amino(ylide)Carbenes.

Cyclic amino(ylide)carbenes (CAYCs) are the ylide-substituted analogues of -heterocyclic Carbenes (NHCs). Due to the stronger π donation of the ylide compared to an amino moiety they are stronger donors and thus are desirable ligands for catalysis. However, no stable CAYC has been reported until today.

Teaching c-phosphanylimines the titanaaziridine coordination mode.

The c-phosphanylimine L1 was employed for the synthesis of the novel titanaaziridine 1 with an intramolecular phosphine donor side following a reductive complexation route. This coordination mode is new for c-phosphanylimines and compound 1 is the first group 4 complex featuring a c-phosphanylimine ligand.

First catalyst-free CO trapping of N-acyliminium ions under ambient conditions: sustainable multicomponent synthesis of thia- and oxazolidinyl carbamates.

The first trapping of N-acyliminium ions by in situ generated carbaminic acid (product of carbon dioxide (CO2) and amine) is reported. This catalyst-free reaction provides a convenient and feasible approach to prepare N-acyl thia- and oxazolidinyl carbamates with good functional-group compatibility and high efficiency under green conditions. Furthermore, the multicomponent method features a broad substrate scope, facile product diversification, smooth scale-up and notable potential for polymer applications.

A One-Step Germole to Silole Transformation and a Stable Isomer of a Disilabenzene.

An unusual germole-to-silole transformation is described. As key intermediates hetero-fulvenes are formed which rearrange to more stable bicyclic carbene analogues. The so-formed germylenes undergo a reductive elimination yielding elemental germanium and siloles.

Early Timing of Thyroidectomy for Hyperthyroidism in Graves' Disease Improves Biochemical Recovery.

Background: The role of thyroidectomy as an early treatment for hyperthyroidism has been poorly investigated. Our aim was to examine its success rates, particularly focusing on thyroidectomy as an early treatment.

Methods: Patients with thyroidectomy for hyperthyroidism between February 2008 and October 2014 were included.

Thyroid cancer has a small impact on patient-partner relationships and their frequency of sexual activity.

Unlabelled: ABSTRACTObjective:This cross-sectional survey examined changes in perceived relationships and sexual activity in a sample of thyroid cancer patients and their partners, taking into account sociodemographic and disease-related variables, as well as such outcome measures as anxiety, depression, fatigue, and quality of life (QoL).

Method: A total of 38 patients with thyroid cancer who were being treated at the department of nuclear medicine in Zürich or Lucerne over the preceding seven years, as well as their partners, completed questionnaires about the quality of their relationships (RQ), about perceptions of changes in their relationships, and about their frequency of sexual activity. They also filled out prevalidated questionnaires related to anxiety, depression, fatigue, and QoL.

Pausing guides RNA folding to populate transiently stable RNA structures for riboswitch-based transcription regulation.

In bacteria, the regulation of gene expression by cis-acting transcriptional riboswitches located in the 5'-untranslated regions of messenger RNA requires the temporal synchronization of RNA synthesis and ligand binding-dependent conformational refolding. Ligand binding to the aptamer domain of the riboswitch induces premature termination of the mRNA synthesis of ligand-associated genes due to the coupled formation of 3'-structural elements acting as terminators. To date, there has been no high resolution structural description of the concerted process of synthesis and ligand-induced restructuring of the regulatory RNA element.

[CME: Radioactive iodine therapy in thyroid cancer].

Differentiated thyroid carcinomas represent about 90% of all thyroid tumors and are divided in papillary and follicular carcinomas. Their prognosis is good, however, recurrences are not rare. Their ability to accumulate iodine is used for the radioactive iodine treatment.

Visualization of Parathyroid Hyperplasia Using 18F-Fluorocholine PET/MR in a Patient With Secondary Hyperparathyroidism.

Several imaging modalities exist for the detection of parathyroid adenomas in patients with primary hyperparathyroidism. Unlike solitary parathyroid adenoma, parathyroid hyperplasia in patients with secondary hyperparathyroidism hitherto is difficult to assess with any imaging modality. Our case of a young patient with chronic kidney failure illustrates that F-fluorocholine PET/MR might be an imaging tool suitable for the diagnosis and presurgical assessment of parathyroid hyperplasia.

Perception of treatment burden, psychological distress, and fatigue in thyroid cancer patients and their partners - effects of gender, role, and time since diagnosis.

Objectives: The aim of this study was to examine diagnosis and treatment burden as well as psychological distress (anxiety and depression) and fatigue in thyroid cancer patients and their partners, focusing on the effects of gender, role, and time since diagnosis.

Methods: Seventy-one patients diagnosed and treated for differentiated thyroid cancer within the past 7 years, participated in this online study, as well as 40 partners. Standardized questionnaires were used rating anxiety, depression, fatigue, and quality of life.

Sensitivity and Specificity of Dual-Isotope 99mTc-Tetrofosmin and 123I Sodium Iodide Single Photon Emission Computed Tomography (SPECT) in Hyperparathyroidism.

Purpose: Despite recommendations for 99mTc-tetrofosmin dual tracer imaging for hyperparathyroidism in current guidelines, no report was published on dual-isotope 99mTc-tetrofosmin and 123I sodium iodide single-photon-emission-computed-tomography (SPECT). We evaluated diagnostic accuracy and the impact of preoperative SPECT on the surgical procedures and disease outcomes.

Methods: Analysis of 70 consecutive patients with primary hyperparathyroidism and 20 consecutive patients with tertiary hyperparathyroidism.

profiling reveals immunomodulatory effects of sorafenib and dacarbazine on melanoma.

Sorafenib is a multi-kinase inhibitor used alone or in combination with dacarbazine to treat metastasized melanoma. Our study investigated the relationship between metabolic response assessed by PET-CT and global transcriptome changes during sorafenib and dacarbazine therapy in patients with advanced melanoma. We conducted an open-label, investigator-initiated study that enrolled 13 sorafenib-naïve Stage IV melanoma patients, whose metastases were accessible for repeated biopsies.